Many lung disorder patients (cystic fibrosis, COPD) require supplemental oxygen. Studies show both quality and length of life improve if patients maintain active lifestyles. Liquid and gaseous oxygen provide needed mobility but are expensive and require patients to routinely return to supplemental oxygen supply. Oxygen enriching air (OEA) membrane systems could provide needed portability at lower cost. Phase I demonstrated proof of concept by: (1) Producing OEA from membranes above targeted flux levels (2) Designing 5 pound system to supply 2 liters/minute (LPM) oxygen equivalent (3) Demonstrating membrane durability In Phase II the focus is on designing, building, and evaluating prototype systems. Key tasks are: (1) improve membrane performance and fabricate prototype OEA membrane modules with target productivity (e.g. 2.0 LPM Oxygen Equivalency) (2) Design, prepare, and evaluate membrane module system including membrane from above, pump, battery pack and supporting hardware weighing less than 8 lbs (3) With respiratory care companies evaluate membrane module system in clinical trials. Four respiratory care companies have (1) committed in-kind funding to conduct these clinical evaluations with an estimated value to NIH of $ 1.5 million and (2) provided key equipment and design components. PROPOSED COMMERCIAL APPLICATION: Successful completion of this project would make portable membrane enriching systems cost effective and more convenient alternatives to the 100,000 concentrators and liquid/gas oxygen systems sold domestically. At $ 1000 per device the potential market for an improved system is $ 100 million domestically and a similar additional amount worldwide.